1. Field of the Invention
This invention relates to an electrical contact or contact member having a pair of contact piece portions for resiliently holding a lead wire of an electric part to electrically contacting the electrical contact with the lead wire.
2. Related Art
There is known a socket of the type in which a movable plate is mounted on an upper surface of a socket body for lateral movement so as to bring lead wires of an IC package into and out of engagement with respective electrical contacts mounted on the socket body. Each electrical contact has a pair of contact piece portions for holding the lead wire therebetween.
One such socket is of the type in which the movable plate is moved laterally to urge the pair of contact piece portions of each electrical contact away from each other, and then the IC package is placed on the movable plate, so that each lead wire of the IC package is inserted through the movable plate into a gap between the pair of contact piece portions of the corresponding electrical contact, mounted in the socket body, without applying a load. Another such socket is of the type in which the IC package is placed on the movable plate, and each lead wire of the IC package is brought into a position adjacent to the corresponding electrical contact, and then the movable plate is laterally moved together with the IC package, so that the wire lead of the IC package is introduced between the pair of contact piece portions of the corresponding electrical contact.
In the latter socket, a wiping effect can be expected when laterally moving the IC package so as to introduce the lead wire between the pair of contact piece portions, thus achieving an advantage that the reliability is enhanced. This contact type has been extensively used for PGA-type ICs.
One electrical contact of such a contact type is disclosed, for example, in U.S. Pat. No. 4,412,713. As shown in FIGS. 19 to 22, this electrical contact includes a pair of left and right contact piece portions 1 and 2 formed by blanking, and a pair of lead holding portions 3 and 4 formed respectively by perpendicularly bending upper end portions of the contact piece portions 1 and 2.
The two lead holding portions 3 and 4 are bent along respective folding lines 5 passing horizontally across blanked-out surfaces 1a and 2a of the contact piece portions 1 and 2, so that each contact piece portion 1, 2 assumes a generally inverted L-shape. As a result, a lead receiving slot 6 is formed between the two holding portions 3 and 4.
The IC lead wire is moved laterally into the lead receiving slot 6 through an outer open end thereof. At this time, the IC lead wire is rubbed by blanking shear surfaces 1b and 2b of the lead holding portions 3 and 4 defining the slot 6, thus achieving a wiping effect.
The electrical contact of the above construction has the above-mentioned advantage; however, the lead receiving slot 6 between the two lead holding portions 3 and 4 is required to have a predetermined width W when the electrical contact is formed by blanking as shown in FIG. 19, and the reduction of the width W of the lead receiving slot 6 is limited because this slot 6 is formed through blanking. Thus, the above electrical contact has a problem that it can not be suited for use with the very thin, high-density design of the IC lead wires that has been developed recently.